This invention relates to a moving picture recording and reproduction apparatus and method as well as a medium, and more particularly to a moving picture recording and reproduction apparatus and method as well as a medium wherein index information for moving pictures is used.
Conventionally, a video cassette recorder (VCR) is known which is used to record a television broadcast and has a function of recording index information such as a broadcasting hour, a channel and a genre of a recorded program at the top of a video cassette tape.
With a VCR having the function described, a user can recognize index information of programs recorded on a video cassette tape only if the top of the video cassette tape is played back. However, detailed contents of the programs recorded cannot be grasped unless the video cassette tape is played back from the top to the last end thereof.
In order to allow a user to grasp detailed contents of programs recorded on a video cassette tape without playing back the entire video cassette tape, for example, the following method may be used. In particular, upon recording, a still picture (or thumbnail picture) is extracted at each fixed time interval from a moving picture signal of a program being recorded, and the still pictures thus obtained are recorded collectively at a predetermined position of the video tape. Then, in order to confirm the contents of the program recorded on the cassette tape, only the predetermined position of the video cassette tape is played back.
Meanwhile, in recent years, increase in capacity and reduction in cost of recording media such as hard disks and increase in speed of processing for compression coding of an AV signal (a moving picture signal and an audio signal) have been and are being proceeded. Various electronic apparatus have been developed making use of such techniques so that an AV signal of a television program can be compression coded and recorded and then reproduced.
Since an electronic apparatus of the type described can record an AV signal of a great number of programs onto a recording medium of a large capacity, it preferably has such a function of extracting still pictures from a picture signal of a program being recorded and recording the still pictures onto a recording medium as described above so that a user can readily grasp AV signals of a plurality of programs recorded on the recording medium.
However, if a still picture is extracted at each fixed time interval from a moving picture signal of a television broadcast as described above, then a still picture which is not suitable to grasp contents of the program (for example, a commercial still picture or the like) may possibly be recorded. Thus, there is a subject to be solved in that still pictures suitable to grasp contents of a program cannot be extracted with certainty.
It is an object of the present invention to provide a moving picture recording and reproduction apparatus and method as well as a medium by which, upon recording of a television program, representative pictures from which contents of a program can be grasped can be recorded.
In order to attain the object described above, according to the present invention, when a moving picture signal of a television program is recorded onto a recording medium, still pictures which characterize contents of the television program and therefore allow contents of the television program to be specified are determined based on a predetermined algorithm and recorded in a reduced size onto the recording medium together with the moving picture signal so that they can be used as indices of the recording medium.
More particularly, according to an aspect of the present invention, there is provided a moving picture recording and reproduction apparatus, comprising recording means for recording a moving picture signal inputted thereto onto a recording medium, extraction means for extracting still pictures at a predetermined sampling rate from the moving picture signal, calculation means for calculating evaluation values of the still pictures extracted by the extraction means using pixel values of the still picture, detection means for detecting a maximum one of the evaluation values calculated by the calculation means, representative picture production means for reducing the size of the still picture corresponding to the maximum one of the evaluation values detected by the detection means to produce a representative picture, recording means for recording the representative picture produced by the representative picture production means onto the recording medium, reading means for reading out a representative picture or pictures from the recording medium, and table production means for applying the representative picture or pictures read out by the reading means to produce a representative picture table.
The detection means may detect a maximum evaluation value from among an arbitrary number of evaluation values per unit time.
The calculation means may use the pixel values of the still picture extracted by the extraction means to determine an accuracy with which a character is present on the still picture and use the accuracy to calculate the evaluation value.
As an alternative, the calculation means may use the pixel values of the still picture extracted by the extraction means to determine an accuracy with which the face of a person is present on the still picture and use the accuracy to calculate the evaluation value.
As another alternative, the calculation means may detect a level of an audio signal corresponding to the still picture extracted by the extraction means and use the level of the audio signal to calculate the evaluation value.
According to another aspect of the present invention, there is provided a moving picture recording and reproduction method, comprising a recording step of recording an inputted moving picture signal onto a recording medium, an extraction step of extracting still pictures at a predetermined sampling rate from the moving picture signal, a calculation step of calculating evaluation values of the still pictures extracted by the extraction step using pixel values of the still picture, a detection step of detecting a maximum one of the evaluation values calculated by the calculation step, a representative picture production step of reducing the size of the still picture corresponding to the maximum one of the evaluation values detected by the detection step to produce a representative picture, a recording step of recording the representative picture produced by the representative picture production step onto the recording medium, a reading step of reading out a representative picture or pictures from the recording medium, and a table production step of applying the representative picture or pictures read out by the reading step to produce a representative picture table.
According to a further aspect of the present invention, there is provided a medium for causing a computer to execute a program which comprises a recording step of recording an inputted moving picture signal onto a recording medium, an extraction step of extracting still pictures at a predetermined sampling rate from the moving picture signal, a calculation step of calculating evaluation values of the still pictures extracted by the extraction step using pixel values of the still picture, a detection step of detecting a maximum one of the evaluation values calculated by the calculation step, a representative picture production step of reducing the size of the still picture corresponding to the maximum one of the evaluation values detected by the detection step to produce a representative picture, a recording step of recording the representative picture produced by the representative picture production step onto the recording medium, a reading step of reading out a representative picture or pictures from the recording medium, and a table production step of applying the representative picture or pictures read out by the reading step to produce a representative picture table.
With the moving picture recording and reproduction apparatus, the moving picture recording and reproduction method and the program of the medium, an inputted moving picture signal is recorded onto a recording medium, and still pictures are extracted at a predetermined sampling rate from the moving picture signal. Then, evaluation values of the still pictures thus extracted are calculated using pixel values of the still picture, and a maximum one of the evaluation values thus calculated is detected. Thereafter, the size of the still picture corresponding to the detected maximum evaluation value is reduced to produce a representative picture, and the representative picture thus produced is recorded onto the recording medium. Further, a representative picture or pictures are read out from the recording medium, and the representative picture or pictures thus read out are applied to produce a representative picture table. Consequently, when a television program is recorded, a representative picture or pictures from which contents of the program can be grasped can be recorded onto a recording medium.